The present invention relates to the electromagnetic antenna art and particularly to the art of antennas that are electrically small, as well as being operational over a wide bandwidth and on several frequencies within the bandwidth at the same time without adjustment. A long standing and continuing goal in the antenna art has been, and is, to provide effective antennas that require the least amount of physical space. A small single antenna that will operate effectively over a relatively broadband of frequencies is highly desirable with any variable frequency or tunable transmitter or receiver system. For instance it is very beneficial to military vehicles whether they be airplanes, tanks, or submarines to have the smallest number and smallest size antennas that are feasible to maintain effective communication.
VHF antennas currently in use on U.S. military vehicles have the disadvantage of being over ten feet high and 0.75 inches thick. They thus present stowage problems, are visible to the enemy at considerable distances and frequently encounter obstacles which transmit damaging shocks to the antenna base and mounting structure. Further, these antennas have an electro-mechanical tuner built into the base consisting of coils, capacitors, rotary switch mechanisms, and a stepping motor, all subject to failure because of moving parts and corrosion when the base housing leaks. The RC-292, mast mounted VHF antenna, is currently in use by the military for land-based, fixed portable applications. This antenna has the disadvantages of being heavy, having rigid ground plane elements making it cumbersome to erect, and having elements which must be changed twice in order for it to be operated throughout the frequency range of 30-76 MHz. Other military broadband antennas having multiple frequency capability have the disadvantages of being extremely high vertically and of having threaded sections that are subject to loosening in vibration and requiring a base spring which is RF "hot", thus subjecting the antenna to shorting to ground by salt spray in amphibious vehicle applications.